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    <title>Document</title>
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        window.onload=function()
        {
            class Person{
                static [Symbol.hasInstance](param){
                    console.log(param);
                    console.log("我被用来检测类型了");
                }
            }
            let o={};
            console.log(o instanceof Person);

            const arr=[1,2,3];
            const arr2=[4,5,6];
            arr2[Symbol.isConcatSpreadable]=false;
            console.log(arr.concat(arr2));
            const arr3=arr.concat(arr2);
            console.log(arr3[3][1]);
        };
    </script>
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